note 121103 added to datetime.add

What you can do with this function/method is a great example of the philosophy: "just because you can do it doesn't mean you should". I'm talking about two issues: (1) the number of days in the month which varies from months 1-12 as well as for month 2 which could be leap year (or not); and then issue (2): what if there is the need to specify a large quantity of an interval such that it needs to be re-characterized into broader-scoped intervals (i.e. 184 seconds ==> 3 minutes-4 seconds). Examples in notes elsewhere in the docs for this function illustrate both issues and their undesired effects so I won't focus on them further. But how did I decide to handle? I've gone with four "public" functions and a single "private" function, and without giving you a bunch of code to study, here are their summaries... 1. function adjustYear(int $yearsAdj){ //you can pass in +/- value and I adjust year value by that value but then I also call PHP's 'cal_days_in_month' function to ensure the day number I have in my date does not exceed days in the month for the new year/month combo--if it does, I adjust the day value downward. 2. function adjustMonth(int $monthsAdj){ //same notes as above apply; but also, I allow any number to be passed in for $monthsAdj. I use the 'int' function (int($monthsAdj/12)) and modulus % operator to determine how to adjust both year and month. And again, I use 'cal_days_in_month' function to tweak the day number as needed. 3. function addTime(int $days, int $hours, int $minutes, int $seconds){ // I use date_add and create a DateInterval object from the corresponding string spec (created from the args passed to this function). Note that months and years are excluded due to the bad side-effects already mentioned elsewhere. 4. function subtractTime(int $days, int $hours, int $minutes, int $seconds){ //notes for "addTime" also apply to this function but note that I like separate add and subtract functions because setting the DateInterval property flag to indicate add/subtract is not as intuitive for future coding. 5. function recharacterizeIntervals(int $days, int $hours, int $minutes, int $seconds){ // I convert excessively large quantities of any one interval into the next largest interval using the 'int' function and modulus (%) operator. I then use the result of this function when creating the string interval specification that gets passed when generating the DateInterval object for calling the date_add function (or object-method equivalent). **Results/goals... --any number of days/hours/minutes/seconds can be passed in to add/subtractTime and all of "Y/M/D/H/M/S" values get adjusted as you would expect. --using adjustYear/Month lets you pass +/- values and only "Y/M" values get modified without having undesirable effects on day values. --a call to the "recharacterize" function helps ensure proper and desired values are in the intervals prior to calling date_add to let it do its work. ---- Server IP: 72.52.91.14 Probable Submitter: 24.158.119.193 ---- Manual Page -- http://php.net/manual/en/datetime.add.php Edit -- https://master.php.net/note/edit/121103 Del: integrated -- https://master.php.net/note/delete/121103/integrated Del: useless -- https://master.php.net/note/delete/121103/useless Del: bad code -- https://master.php.net/note/delete/121103/bad+code Del: spam -- https://master.php.net/note/delete/121103/spam Del: non-english -- https://master.php.net/note/delete/121103/non-english Del: in docs -- https://master.php.net/note/delete/121103/in+docs Del: other reasons-- https://master.php.net/note/delete/121103 Reject -- https://master.php.net/note/reject/121103 Search -- https://master.php.net/manage/user-notes.php